Apparatus for extracting tubes from heat exchangers and the like has already been proposed. An example of such an apparatus is disclosed in GB 2,113,598A. However, such an apparatus is of relatively elaborate and complex structure, and this is reflected in the complexity of the mode of operation of the apparatus. Accordingly, improvements are desirable in relation to the simplifying the construction and operation of the apparatus, its cost, its space requirements, particularly axial length, and indeed its reliability. An area in such prior apparatus which particularly calls for improvement concerns the method of gripping the article to be extracted, and the present invention is particularly, though not exclusively, concerned with providing improvements in this respect.
Accordingly, an object of one aspect of the present invention is to provide an extraction apparatus for tubes and like elongated articles providing improvements in relation to one or more of the matters discussed above or generally.
According to a first aspect of the invention there is provided an extraction apparatus for tubes and like elongated articles as defined in claim 1 of the accompanying claims.
A second aspect of the invention concerns the means for applying an extraction load to the article concerned.
Prior proposals in this regard include the use of a collet assembly mounted within the tubular piston rod of the hydraulic ram assembly, whereby an extraction load is transferred radially inwards through a collet head or chuck to the collet jaws, and thus to the article.
While this prior proposal may well operate satisfactorily in laboratory test conditions, it is found that in actual normal use conditions, it is subject to significant problems and shortcomings. These concern not only the size and weight of the apparatus, but also a tendency to cease-up and jam in use, whereby the apparatus becomes unusable, service is imperative, and it is then found that it is extremely difficult to detach the jammed collet assembly for servicing purposes, and later to replace it.
Accordingly, it is an object of this second aspect of the present invention to provide improvements in relation to one or more of the matters discussed and disclosed herein, or generally.